Steam generator



May 30, 1933. HUET 1,912,204

STEAM GENERATOR Filed Sept. 20, 1930 INVENTOR fid/ BY a/w ATTORN EY Patented May 30, 1933 UNETED STATES PATENT OFFICE ANDRE HU ET, F PARIS, FRANCE, ASSIGNOR TO THE SUPERHEATER COMPANY, OF NEW YORK, N. Y.

STEAM GENERATOR Application filed September 20, 1930, Serial No. 483,231, and in France May 1, 1930.

In boilers with high rates of evaporation the tubes with which the hot gases first come in contact evaporate much more water than tubes placed immediately above them. This is true both in boilers in which the water is evaporated directly as well as in boilers Working indirectly and employing a closed primary circuit.

The present invention has for its object the 1 provision of an evaporating bundle of tubes whereby one may be assured that in any type of boiler in which evaporation by the hot gases is accomplished in serpentine water tubes, all the tubes or coils have a positive supply of water and that the steam produced in the several parts of the evaporating bundle may be readily liberated. The essential feature of the evaporating tube bundle form ing the object of the present invention consists in having the tubes divided into two or more groups at least one of which includes the tubes exposed to the fire so that they constitute relatively small independent circuits which are, however, interconnected. In addi tion, provision is made to feed water directly in each of the groups without making the water flow through the other groups.

In this fashion the losses incurred through feeding are reduced to a minimum. As a corn sequence the feeding is easily accomplished, as such feedin is provided for each of the cir cuits. The danger that some of the tubes or portions of some of them may be supplied with iiisuliicient water is very much reduced.

Moreover, the steam is readily liberated without passing through other groups of the vaporizing bundle and is carried ofi' without difliculty.

There is therefore no entrainment of water.

The steam is therefore of better quality and the tubes run no danger of being filled entirely with steam.

The description which follows and which refers to the accompanying drawing and as which is given by way of example will make clear the manner in which the invention may be carried into practice.

Fig. 1 of the drawing shows a transverse section of an evaporating bundle according C to my invention;

Fig. 2 is a variation.

In both figures corresponding elements are designated by the same reference numerals.

In Fig. 1 there is arranged between the walls 1 and 2 the evaporating tube bundle whose lower part is made up of tubes or serpentines 3 and whose upper part comprises the tubes or serpentines 4;.

The tubes 3 are connected at their lower extremities 5 to a header 6 which supplies water and by their upper extremities 7 to the header 8 where the water is separated out. The tubes 4 have their lower ends 9 connected to the separator header 8 and their upper ends 10 to the water separator 11. The water which is to be evaporated in the vaporizer bundle is supplied by the feed line 12 and the steam generated is directed by the conduit 16 to the point of use. This use may be any, for example, for a steam engine, a turbine, etc. in which the steam is directly used, or the steam may be carried to the vaporizing tubes or coils of an indirect boiler. In other Words to the closed primary circuit of such a boiler. In the latter case the feed pipe 12 will be the pipe by which the water produced by the condensation of the primary steam in the vaporizing elements is returned to the header 6 to recommence the same circuit.

The headers 6 and 8 are connected by means of the riser 13 through which a part of the feed-Water can flow directly from the header 6 to the header 8 without passing through the tubes 3.

The headers 8 and 11 are connected by two tubes 14 and 15. One or" these, for example, 14 is of a materially larger diameter than the other one 15. More will be said further on about the function of these two tubes.

The action of the apparatus is as follows: One portion of the feed-water brought in to the header 6 flows through the tubes 3. In these tubes 3 which are nearest to the source of heat a rapid evaporation occurs and the resulting steam accompanied by such water as has not been vaporized in the tubes 3 reaches the header 8 where these two fluids, the steam and the water separate from each other, the water joining the feed-water brought in by the tube 13.

The steam coming from the tubes 3 rises directly to the header 11 without flowing through the tubes -l. This point will be referred to again further on.

The teed-water brought into the header 8 by the tube 13 passes into the tubes 1', where it e aporat The steam resulting trpm this evaporation in the. tubes 4 accompanied by such wa er as is not vaporized reaches the header .1 whe e the two fluids are separated. The steam flows toward the tube 16 and so to the point or use, together with the steam coming from the tubes 3. whereas the water which has collected in the header 11 fl0ws back to the header 8 to start again its circuit of evaporation through the tubes 4.

In Fig. 2 the arrangement is the same as that iustdescribed except that the header 8 1s replaced by two headers 17 and 18 connected by a pipe 19 which in a way forms a prolongation of the tube 3 and that t header 118 18 receives teed-water from the tube 12 dircctly through the connection 20 in addition to what it may receive through the connec- It has been stated above that the tubes 14.- and 15 are of substantially different diameters. the tube 14 for example being of a materiallv larger diameter than the tube 15. lVith this arrangement even it the tubes 14 and 15 are arranged simply as shown in Fig. 2. the steam will select for its passage the larger diameter tube 14 where the resistance is and will reach the header 11 through it. The water separated out in the header ll will return through the tube 15.

To enhance the circulation indicated. the tubes ll and 15 may be arranged as shown in Fig. 1, the steam tube 1f; opening from the header 8 at its highest point and opening into the upper portion of the header 11 whereas the return water tube 15 is connected to the lower parts of the headers 8 and 11. It will be readily seen that with the arrangements described above there will. be tormed complete local circulations much shorter than the circulation existing in the case or an evaporating tube bundle in one piece. For X- ample. the steam produced in the tubes 0 tlows to the point at use without flowing through the tubes The water not vaporized in the tubes Jr w ll be returned to the header 8 or 18 and r .rncd into the circulation of the tules without having to pass through the tubes 3. Moreover, there will be a local circulation through the tubes 1% and 15 and the headers to which they are connected. the steam rising on the one hand through the tube 14. and water descending on the other hand through the tube 15.

The friction losses in each of the circuits are very small.

In addition, the direct (lQllVQlY of feedwater to the collectors to which the lower ends of the tubes l are connected assures that they will always be supplied with water while if they followed the tubes 3 directly, these tubes 4, in case the tubes 3 h ad a lively evaporation, would be traversed only by steam, which would be a serious matter and which would diminish the outputot the boiler.

It will be understood that variations can be made in the arrangements described without going outside of the scope of the invention. Thus, the tubes 13, 14:, 15 and 19 may be single tubes or there may be a plurality of them without this resultin in any real change in the invention. The evaporating tube bundle may be composed of more than two su )erimposed portions.

lVhat I claim is:

1. In a boiler, a. water header, an intermediate header, means feeding water to said water header, means feeding water and steam to said intermediate header, a separator. a group of tubes connecting the latter header with said separator and disposed in the path of gases for vaporizing the water therein to steam, and normally open water return means connecting said separator and intermediate header.

2. In a boiler, a water header, intermediate header means, a separator, means feeding water to said water header, means continuously feeding water and steam to said intermediate header means, a group of tubes connecting the latter with said separator, said tubes being disposed in the path of gases for translating the water therein into steam,

ater return means connected to said separator and the aforementioned header means, and supplementary means connecting the alter header and said intermediate header for continuously feeding water to the latter.

3. In a boiler, a water header, an intermediate header, a separator, means feeding water to said water header, tubes connecting said headers and disposed in the path of gases adapted to be continuously ted with water from said water header and direct wator and steam into the intermediate header, tubes disposed in a lower temperature zone in the path or" gases connecting the intermediate headcr and separator adapted to re ccive water from the intermediate header to generate steam. and normally open means by passing the last mentioned tubes for direct- Kid ing the steam from the intermediate header into said separator.

4. In a boiler, a. water header, an intermediate header, a separator, means continuously feeding water to said water header, tubes connecting said headers and disposed in the path of gases adapted to be continuously fed with water from said 'ater h ader and direct heated water and the generated steam into the intermediate header, tubes disposed in a lower temperature Zone of: the path of gases connecting said intermediate header and separator adapted to receive heated water from the intermediate header to generate steam, means to direct the steam from the intermediate header to said separator and by-passing the second mentioned tubes, a water return connecting the separator with the intermediate header, and supplementary water feeding means connecting said headers.

5. In a boiler, a plurality of superposed headers comprising a water header, an inter mediate header and a separator, water evaporating means disposed in the path of gases connecting adjacent headers, and means for continuously and simultaneously feeding water to said intermediate header from a plurality of sources.

6. In a boiler, a plurality of superposed headers comprising a water header, a separator and intermediate header means, a group of tubes connecting adjacent headers and disposed in the path of gases, and means for simultaneously feeding water to the intermediate header means from said water header, separator and the group of tubes connecting the intermediate header means with said water header.

7. In a boiler, a plurality of superposed headers, comprising a water header, intermediate header means, and a separator, a group of tubes disposed in the path of th. hot gases connecting said water header and intermediate header means, a group of tubes disposed in a zone of a lower temperature in the path of said gases connecting the separator and said intermediate header means, means for supplying said water header with water, means for continuously feeding water to the intermediate header from the water header, the separator, the group of tubes associated with said water header and from said water supply means.

8. In a boiler, a water header, means feeding Waterto said Water header, a pair of separators at different levels, a riser connectmg said water header with the lower one of said separators to feed Water thereto, a group of tubes connected to said lower separator and said water header, said tubes being disposed in the path of hot gases whereby water from said water header is conducted through said tubes into the said lower separator, a steam conduit connected to and continuously in free communication with said separators, and a group of tubes connecting said separaters to receive heated water continuously from the lower separator, said conduit being adapted to by-pass the steam generated in the first mentioned group of tubes across the second mentioned group to the upper separator of said pair.

9. In a boiler, a water header, means feed ing water to said water header, a pair of separators, a riser connecting said water header with one oi said separators to supply water thereto, tubes connected to the last mentioned separator and said water header and disposed in the path of hot gases to conduct water and steam from said tubes into the last mentioned separator, a steam conduit interposed between said separators, tubes having a greater length than the first mentioned tubes connecting said separators being disposed in a zone of a lower temperature in the path of said gases to receive heated water from said first mentioned separator and generate steam received in the other separator of said pair.

10. The combination according to claim 9 characterized in that means is provided for directing water in the last mentioned separator to the first in such a way as to by-pass the water header.

11. In a boiler, a water header, means feeding water to said water header, a pair of separators, a riser connecting said water header with one of said separators to supply Water thereto, tubes connected to the last mentioned separator and said water header and disposed in the path of hot gases to conduct water and steam from said tubes into the last mentioned separator, a steam conduit interposed between said separators and in free communication therewith, tubes having a greater length than the first mentioned tubes connecting said separators and being disposed in a zone of a lower temperature in the path of the said gases to receive heated Water continuously from said first mentioned, separator and enerate steam to be re ceived in the other separator of said pair, and a conduit of less diameter than the first mentioned conduit for passing water directly from the last mentioned separator to the first.

12. A vaporizing apparatus comprising a piurality of superposed groups of steam generating water tubes in free communication and arranged serially in the path of heating gases, one of said groups having relatively short tubes and being exposed to the fire, the aforementioned groups each being provided with an independent feed water connection, a second one of said plurality of groups having relatively longer tubes, a steam and water separator into which said lastunentioned group is connected, and means whereby steam generated in the shorter group of tubes is conducted to said separator so as to bypass the longer tubes.

1.3. A vaporizing apparatus comprising a plurality of superposed groups of steam generating water tubes normally in free communication and arranged serially in the path of the heating gases, headers to which the ends of said tubes are connected and down-comer means individual to the second of said groups in the direction of the gas flew and directly connecting the headers for such group, one of said groups having relatix'ely shert inhes and being exposed to the fire, the aforementioned groups each being provided with an independent feedwater connection.

ANDRE HUET. 

